Timer = function(callback,during){
	this._callback = arguments[0];
	if(arguments.length==2){
		this._during = arguments[1];
	}
	this._init();
};
Timer.prototype = {
		_during:1000,
		_callback:null,
		continued:0,
		_tmr:null,
		//----------------------------------------------------------------------------------------------//初始化
		_init:function(){
		},
		//----------------------------------------------------------------------------------------------//开始计时
		start:function(){
			this._tmr = setInterval($.proxy(this._onTick,this), this._during);
		},
		//----------------------------------------------------------------------------------------------//结束计时
		stop:function(){
			clearInterval(this._tmr);
		},
		//----------------------------------------------------------------------------------------------//触发事件
		_onTick:function(){
			this.continued += this._during; 
			this._callback(this); 
		}
};